Numbers k such that k and k^2 use only the digits 2, 4, 7 and 9.
A137108
Numbers k such that k and k^2 use only the digits 2, 4, 7 and 9.
Terms
- a(0) =2a(1) =7a(2) =27a(3) =49777a(4) =4994777a(5) =49994777a(6) =499979277
External references
- oeis: A137108